Figure 2. Plateau potentials in ClCadr muscle.
For A–D, the insets show portions of the traces on an expanded time base. (A) The response of muscle from an unaffected littermate to injection of 200 ms of depolarizing current (horizontal bar below the voltage trace); note that action potentials stop when current stops. (B–D) Traces of myotonia triggered by a 200 ms injection of depolarizing current from three different ClCadr muscle fibers. The following membrane potentials are identified in C and D: membrane potential prior to stimulation, initial membrane potential during the plateau potential, membrane potential prior to the termination of the plateau potential, and membrane potential following repolarization. (E) Development of a plateau potential during repetitive stimulation at 8 Hz (stimuli represented by vertical hash marks under the recording).